1. Field of the Invention
The invention pertains to earth working equipment, more particularly to a device for attachment behind a towing vehicle, the device comprising a trench forming blade for lifting soil and a cable laying guide associated with the blade assembly. The blade assembly vibrates vertically and has an eccentric mounting structure for connecting the blade to its supporting structure for vertical adjustment while maintaining a desired angle of attack. The cable laying guide has a vertically adjustable connection with the blade assembly for maintaining proper elevational relationship therebetween.
2. Description of the Prior Art
Cable laying plows are known having vibratory means or vertically oscillatable sawing means mounted on the plow forward edge. Cable laying plows are also known with means for maintaining a desired angle of attack. The following patents exemplify the state of the prior art:
U.S. Pat. Nos: 3,802,210--Apr. 9, 1974, 3,348,383--Oct. 24, 1967, 3,777,500--Dec. 11, 1973, 3,608,322--Sept. 28, 1971, 3,726,099--Apr. 10, 1973, 3,405,533--Oct. 15, 1968, 3,286,476--Sept. 30, 1963.
None of these patents, however, discloses the specific structure of the cable laying device of the present invention, nor is any device illustrated therein specifically adapted for use with frozen soil. Furthermore, these devices fail to provide a combination of an efficient blade angle of attack, a soil elevator, and cable laying guide attachment means so as to cause the soil to raise while simultaneously maintaining a suitable cable laying guide angle, with the result that such deficiencies in prior art devices cause the cable to bend or drop as it exits from the guide, resulting in undesirable permanent cable deformation.